Neurocognitive Impairment is Common among HIV Positive Children and Adolescents

		SUMMARY: Children and adolescents who were infected with HIV through mother-to-child transmission may have a high risk of neurocognitive impairment, according to a study described in a letter to the editor in the September 1, 2010 Journal of Acquired Immune Deficiency Syndromes. While the number of children in this analysis was small, the findings suggest that neurocognitive problems in people with HIV are not solely related to aging.

By Liz Highleyman

Studies have shown that HIV-related neurocognitive impairment remains common despite effective antiretroviral therapy (ART). One recent study found a frequency of about 25%.

Some experts have suggested that neurocognitive impairment among HIV positive people is largely attributable to the fact that this population is now living long enough, thanks to ART, to develop normal age-related problems. Others have noted that HIV appears to accelerate the aging process and speed development of progressive age-related conditions. But cognitive impairment among young people with HIV -- particularly those who have been infected their entire lives -- has not been extensively studied.

Yasotharan Paramesparan from Imperial College London and colleagues looked at neurocognitive function in 2 groups of HIV positive individuals. Participants in the younger group were 16 to 25 years of age, while the older group was over 60.

"High rates of HIV encephalopathy and cognitive impairment are well described in infants and children with vertically acquired HIV infection," the study authors noted as background. "Despite reductions in incidence due to the availability and wider use of combination antiretroviral therapy, learning, behavioral, and motor deficits commonly persist."

The investigators conducted a detailed computerized neurocognitive assessment (known as Cogstate) to test multiple cognitive domains including psychomotor function, executive function, memory, and attention. They also used the International HIV Dementia Scale, a validated tool that incorporates timed finger tapping, sequential movement, and verbal recall.

The analysis included 6 younger and 31 older HIV positive participants. The average age of younger group was 19 years (range 17-23 years) and the older group had a mean age of 65 years (range 60-77 years). All participants in the younger group had vertically acquired, or perinatal, HIV infection.

All of the older participants and 4 of the younger ones were on combination ART and had undetectable plasma viral load for a minimum of 3 months. Immune function was well preserved, with average CD4 cell counts of 618 and 575 cells/mm3 in the younger and older groups, respectively. People with other conditions that could affect cognitive function, including history of recreational drug use, active opportunistic infections, hepatitis C coinfection, or any neurological disease or symptoms, were excluded.

Results

	4 of 6 younger participants (66.7%) and 6 of 31 older individuals (19.4%) met the diagnostic criteria for neurocognitive impairment.
	In a linear regression analysis, the presence of neurocognitive impairment was significantly associated with younger age (P = 0.048) and being in the younger study group (P = 0.016.
	There was a trend toward higher rates of neurocognitive impairment among females, but this did not reach statistical significance (P = 0.08).
	In a multivariate analysis, only being in the younger study group remained a significant predictor of neurocognitive impairment.

"This pilot study reveals high rates of asymptomatic neurocognitive impairment in perinatally infected HIV positive young adults (67%) when compared with older subjects (19%)," the researchers wrote. "Such rates greatly exceed those observed in the cohorts of horizontally infected young adults, which we and others have assessed previously."

Furthermore, they added, "these results may be an underestimation of true neurocognitive impairment prevalence in perinatally infected young adults." Of approximately 57 young adults attending their adolescent HIV clinic, only 6 were neurologically asymptomatic and therefore eligible for the study. None of the 6 had a history of prior AIDS-defining events, which is associated with increased risk for cognitive impairment among older people.

Although the study included only a small number of younger participants, it demonstrates that aging is likely not the only factor contributing to neurocognitive problems in people with HIV.

Investigator affiliations: Division of Medicine, Imperial College London, UK; Department of HIV Medicine, Imperial College Healthcare NHS Trust, London, UK; 900 Clinic, Imperial College Healthcare NHS Trust, London, UK.

12/10/10

Reference
Y Paramesparan, LJ Garvey, J Ashby, and others. High rates of asymptomatic neurocognitive impairment in vertically acquired HIV-1-infected adolescents surviving to adulthood. Journal of Acquired Immune Deficiency Syndromes 55(1): 134-136. September 1, 2010.